I love how he smiles like he's amused by anyone thinking he could possibly do anything harmful but in the end everyone believes, everyone but 6 people

I love how he smiles when he realizes that John isn't like everyone else. John doesn't immediately assume he's the murderer, and that just makes Sherlock so happy and relieved. :-) I love their friendship

That smile! It's a real, happy smile, like the one you might get when suppressing laughter, or trying not to smile. And that was pretty much the first day or so that he knew John. I don't ship Johnlock, but John made Sherlock smile in less than two days.